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Question 1
Incorrect
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During which phase of meiosis does exchange of genetic material occur accounting for genetic diversity between individuals:
Your Answer: Anaphase 1
Correct Answer: Prophase 1
Explanation:Prophase 1 has been divided into five different stages ( laptotene, zygotene, pachytene, diplotene ans diakinesis). In prophase 1 chromosomes are going to condense to become visible, each chromosome will contain two chromatids that are joined at the centromere. the nucleolus and nuclear envelope are going to disintegrate. the homologous chromosomes will form tetrad and crossing over will occur between the chromosomes (random exchange of genes), the point of exchange is known as the chiasmata, this increases genetic diversity.
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This question is part of the following fields:
- Genetics
- Physiology
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Question 2
Incorrect
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Question 3
Incorrect
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Which of the following prolongs Prothrombin time?
Your Answer:
Correct Answer: Factor V deficiency
Explanation:Prothrombin time is increased in:- Factor V deficiency- Vitamin K deficiency (which affects factors 2,7 and 10)- Warfarin therapy- Severe liver failureProtein C is an anticoagulant and deficiency results in a hyper-coagulable state with tendency towards thrombosis.
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This question is part of the following fields:
- Cell Biology
- Physiology
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Question 4
Incorrect
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Regarding the myofilament molecules, which of the following contains binding sites for calcium that helps to initiate contraction?
Your Answer:
Correct Answer: Troponin c
Explanation:Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin and troponin C contains the binding sites for the Ca2+ that helps initiate contraction.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 5
Incorrect
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Which cells produce the immunoglobulin proteins involved in mediating humoral immunity?
Your Answer:
Correct Answer: Differentiated forms of B lymphocytes known as plasma cells
Explanation:After the B cells have been activated by a certain antigens, they transform into plasma cells. These plasma cells are responsible for the generation of antibodies (or immunoglobulins Ig) which are also known as regulators of humoral immunity. There are fives classes of Ig: IgA, IgG, IgM, IgE and IgD
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This question is part of the following fields:
- Immunology
- Physiology
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Question 6
Incorrect
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All of the following are consistent with the indicator dilution method except---
Your Answer:
Correct Answer: In thermodilution, the indicator used is warm saline
Explanation:In thermodilution, the indicator used is cold saline.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 7
Incorrect
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The isoforms of nitric oxide synthase which are found in the nervous system (NOS1) and endothelial cells (NOS3) are activated by agents that increase which of the following intracellular electrolytes?
Your Answer:
Correct Answer: Ca
Explanation:Synthesis of nitric oxide is stimulated by activation of the NMDA receptors by certain agents. This leads to opening of the Calcium channels and an influx of calcium into the cell. This will activate the nitric oxide synthase. Nitric oxide is produced on demand.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 8
Incorrect
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A 24-year-old female presents with a swelling located at the anterior border of the sternocleidomastoid muscle. The swelling is intermittent. On examination, it is soft and fluctuant. What is the most likely diagnosis?
Your Answer:
Correct Answer: Branchial cyst
Explanation:Branchial cleft cysts are congenital anomalies that usually arise from second cleft/pouch, with remnants of the third and fourth pouch are rare. Children are typically born with these congenital lesions; however, they may not be evident for weeks, months, or possibly years. The lesions present as fistulae, cyst, sinus tracts, or cartilaginous remnants due to incomplete obliteration during embryogenesis.They are often asymptomatic, but can often become tender, enlarged, or inflamed with possible abscess formation during episodes of upper respiratory tract infections. The patient can present with purulent drainage of the sinus to skin or pharynx from spontaneous rupture of branchial cleft cyst abscess. The most concerning symptoms include dysphagia, dyspnoea, and stridor due to cyst compression of the upper airway.The physical examination will differ depending on the location of the branchial cleft cyst:- A primary branchial cleft cyst is typically smooth, non-tender, fluctuant mass found between the external auditory canal and submandibular area. It is usually with the parotid gland and facial nerve. Two types of lesions exist. Type 1 is rare and characterized as duplication of the membranous external auditory canal. Type 2 lesions contain both ectoderm and mesoderm elements including cartilage. The patient usually presents with soft tissue mass or draining sinus located on the angle of the mandible or otorrhea, making an otologic exam critical in these cases.- A secondary branchial cleft cyst is located between the lower anterior border of the sternocleidomastoid and the tonsillar fossa of the pharynx. It can be in proximity to the glossopharyngeal and hypoglossal nerve as well as carotid vessels. Compared to the primary branchial cleft cysts, secondary cysts are tender if secondarily inflamed or infected. If it is associated with a sinus tract, a mucoid or purulent discharge may be present on the skin or into the pharynx.The treatment of a branchial cleft cyst is typically elective excision due to the risk of infection or present infection, further enlargement, or malignancy.- Carotid Body Tumour: Painless oropharyngeal or upper anterior triangle of the neck; pulsatile, compressible with a bruit or thrill, mobile from medial to lateral direction.- Bartonella henselae infection is Isolated, mobile, fluctuant, tender, warm, erythematous, > 2 cm near the site of inoculation.- Thyroglossal duct cyst: In the Midline, adjacent to the hyoid bone; rises with deglutition.
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This question is part of the following fields:
- Head & Neck
- Pathology
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Question 9
Incorrect
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In the absence of insulin:
Your Answer:
Correct Answer: Glucose uptake by most of the brain is normal
Explanation:Although it is known that insulin levels affect glucose uptake, oxidation and storage in peripheral tissues, its role in the brain isn’t as clear. However, studies have shown that bulk brain glucose uptake isn’t affected by insulin. Glucose transport into the neurons is GLUT3 dependent, and its transport into glia and brain endothelial cells rely on GLUT1. Insulin isn’t necessary for GLUT1 or GLUT3, which explains why brain glucose uptake isn’t affected by insulin levels.
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This question is part of the following fields:
- Endocrinology
- Physiology
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Question 10
Incorrect
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Concerning surface anatomy, where is the mitral valve found?
Your Answer:
Correct Answer: Situated in the 4th intercostal space left to the sternum
Explanation:The mitral valve is situated in the left 4th intercostal space just beneath the sternum.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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